package edu.scu.declaresys.service.intr;

import edu.scu.declaresys.exception.ExecuteException;
import edu.scu.declaresys.vo.User;

/**
 * 
 * @author: zt
 * @since : 2013-7-5
 */
public interface IUserValidateService
{
	/**
	 * 登录系统
	 *@param userName
	 *@param pswd
	 *@return null if success; not null if failed, contain error message.
	 * @throws ExecuteException 
	 */
	public User login(String loginName, String pswd) throws ExecuteException;
	
	/**
	 * 退出系统
	 *@return
	 * @throws ExecuteException 
	 */
	public String logout() throws ExecuteException;

	
}
